Dry bloodspot sampling has been successful for facilitating remote site sampling collection and transport of samples to a laboratory for analysis.
The methods and materials in this art have been the subject of many patents, including U.S. Pat. No. 5,516,487, which describes the use of various antibiotics or preservatives in combination with a cotton fiber filter paper, as well as the use of multiple application zones on the filter paper, which are isolated from each other by perforations in the filter paper; U.S. Pat. No. 5,508,200, which describes the use of filter papers in a complex integrated analytical system and measurement of chemical reactions on the filter paper matrix; U.S. Pat. No. 5,432,097, concerning digestion of the filter paper with cellulose so that recovery of intact cells can be achieved; U.S. Pat. No. 5,427,953, which concerns measurement of a heavy metal (e.g., lead) from blood samples collected on filter paper; U.S. Pat. No. 5,204,267, which describes preservation of blood samples collected on various filter matrices for glucose analysis; U.S. Pat. No. 4,816,224, which is directed to a multiple layer device for separating plasma or serum from a blood sample collected for glucose analysis; U.S. Pat. No. 4,299,812, pertaining to an improved thyroid function test; and U.S. Pat. No. 4,227,249, which primarily concerns a drying procedure and its effect on the results of an assay measuring somatomedin.
Other patents describing the use of certain blotting materials used in biological assay methods include U.S. Pat. Nos. 5,496,626; 5,460,057; 5,415,758; 4,790,797; and 4,774,192.
However, none of the cited patents relate to, or teach, the use of blood spotting papers useful in association with the analysis of blood for small molecules, such as pharmaceutical compounds and drugs.
The present invention includes the discovery of unexpectedly improved and superior analysis results utilizing the materials that are commercially available and presumed to provide only equivalent results. Thus, the present invention significantly improves the accuracy of the detection of small molecules in blood.